US 2018/0294639 A1Published application

Power safety devices and devices and appliances comprising same

AssigneeEton Solutions Limited

InventorsMan Yau LAW, Hin Hung NG

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Abstract

A power safety device comprising a controller, a load monitor and switching circuitry, wherein the switching circuitry is operable in a first operation state in which a power supply side and a load side are connected by a lower impedance power conduction path or a second operation state when impedance between the load side and the power supply side is high so that hazardous operation current is prevented from flowing from the power source side, through the switching circuitry, and to the load side, wherein the load monitor comprises circuit arrangements to determine and/or monitor load condition on the load side and the controller is to operate the switching circuitry to operate in the first operation state upon detection of a non-hazardous load condition or a predetermined safe load condition on the load side.

Claims19

Dependent claims

A power safety device comprising a controller and power connection circuitry, the power connection circuitry defining a switchable power connection path between a source side and a load side;

wherein the power connection circuitry is switchable by the controller to operate in a first operation state or an on-state in which state impedance between the source side and the load side is very low to permit flow of operation current through the power connection circuitry, or a second operation state or an off-state in which state impedance between the source side and the load side is very high to impede flow of operation current through the power connection circuitry;
wherein the controller is to operate to transmit at least one type of probing signal to the load side when the power connection circuitry is in the off-state, and to evaluate and determine whether a response signal or a plurality of response signals from the load side contains at least one of a plurality of human characteristic responses indicative of direct electrical contact of a human body or a living body on the load side;
and wherein the controller is to operate to switch the power connection circuitry from the off-state to the on-state if the responsive signals are determined to containing no indication or no reasonable indication of direct human or animal body contact on the load side.

Dependencies are inferred from the claim text.